Sarah McDougal (サラ・マクドゥガル Sara MakuDugaru) is a 9-year-old American girl from California and is the adopted daughter of Noriyasu Seta.
Following Seta's return to Japan, Sarah is occasionally left in the care of the Hinata Inn residents, as he feels that Sarah traveling with him on expeditions would be too disruptive to her childhood.

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Sarah's Caucasian skin and blonde hair derive from her mother.
A tomboy at heart, Sarah's only interest is to be with her "Papa" (Noriyasu Seta) and attempts to drive away anyone who gets between them, usually through a series of childish pranks and lies.
As such she will sometimes act "two-faced" to further her own ends; acting like an innocent angel to fool people one moment and acting like a devilish brat the next.

She has a panda-shaped birthmark on her buttocks, which she avoids showing at all costs. This is the reason, at least initially, for Sara's warming up to Keitaro. When one of her pranks went awry, Keitaro ended up exposing the birthmark, allowing both him and Naru Narusegawa to see it.
When bathing in the hotspring, she always wears a swimsuit to cover the mark.

Sara possesses a gift for Jeet Kune Do, learned from Seta, she is also adept at bashing Keitaro with priceless artifacts often pulled out of nowhere; the artifacts quickly became associated with her and became her trademark attack like Naru's Naru Punch and Motoko's Shinmei-ryu attacks.

Born to Julia McDougal, Sarah traveled with her mother and her mother's Archaeology friends; Haruka Urashima and Noriyasu Seta, before Julia's death. Instead of being passed on to her uncle, Noriyasu Seta was given custody of Sarah and the pair quickly became father/daughter team as Seta continued his archaeological adventures with Sarah in tow.

Sarah first encounters Keitaro Urashima when the latter was employed part-time by Seta to work as an assistant in moving various artifacts from location to location. Only wanting Seta for herself, Sarah took an immediate dislike to the newcomer and immediately embarked to pester Keitaro until he quit, however, Keitaro persisted at his job.
When Seta suddenly embarked to a seminar in Osaka, Keitaro was saddled with Sarah as a babysitter. Taking her to Hinata House, she attempted to cause more mischief by going between Keitaro and Naru Narusegawa only to have Keitaro accidentally discover her Panda-shaped birthmark.

Some time later, after being left with the Hinata Residents at Hinoshima by Seta, Sarah tries to pull as mean a prank as possible on Naru and Keitaro so that they would send her back to Seta, however, the prank backfires after she attempts to maroon the pair on an island only to become marooned on the island with them.
After returning to the Hinata House with them she and Kaolla Su quickly form a tight partnership largely due to their love of and pursuit of fun. She joins with Kaolla and Shinobu to form the team Puffy Mushroom in pursuing Keitaro to Pararakelse Island when the latter ran away to the island after believing he had failed his entrance exams yet again.

After alternatively staying with Haruka at the Hinata House and Seta while he was in Japan, Haruka eventually signed Sarah up to attend West Hinata Elementary School as a 5th grader. She later temporarily worked for Kanako Urashima during her attempted take over of the dormitory before joining the other Hinata Residents in deposing her.

Sarah's original concept derived from the scratched idea of the Dorm Owner's child. Her character design was set early in production, so early that she appears in one of the final design sketches for Hinata House.

While each of the pets of Hinata House represent a god of direction and element (Kuro is Byakko (west/metal), Shippu is Suzaku (south/fire), Leon is Seiryuu (east/wood) and Tama is Genbu (north/water)), Sarah has been designed to represent the fifth direction and element (center (china)/earth) through various attributes that associate her with China.